Safety apparatus for elevators



Oct. 8, 1946. J DUNLQP 2,408,758

SAFETY APPARATUS FOR ELEVATORS Filed Oct. 29, 1943 2 Sheets-Sheet l WITNESSES: INVENTOR fi v fame5Pz/0/ap.

M I I AZORNEY Oct. 8, 1946. J. DUNLQP 2,408,758

SAFETY APPARATUS FOR ELEVATORS Filed 001:. 29 1943 2 Sheets-Sheet 2 WITNESSES: -INVENTOR (5 4 I famaspurz/op.

v Y ATTORNEY Patented Oct. 8, 1946 SAFETY APPARATUS FOR ELEVATORS James Dunlop, Ridgewood, N. J., assignor, by mesne assignments, to Westinghouse Electric Corporation, East Pittsburgh, Pa, a corporation of Pennsylvania Application October 29, 1943, Serial No. 508,191

My invention relates to safety apparatus for hydraulically operated elevators and, more particularly, to safety apparatus for elevators of the deck-edge type in which the elevator platform is raised and lowered by a plurality of cables operated by a hydraulic engine.

One object of my invention is to provide for stopping the operation of the elevator engine when any one of its hoisting cables becomes loose or broken.

Another object is to provide a safety apparatus responsive to the slackening or breaking of any one of the hoisting cables on an elevator for stopping the elevator engine, which shall be positive in operation, and simple and inexpensive to manufacture, install, and maintain in operable condition.

For a better understanding of my invention, reference may be had to the accompanying drawings, in which:

Figure 1 is a diagrammatic representation in end elevation of a deck-edge elevator for ships in which the elevator is supported and moved by a plurality of hoisting cables operated by a hydraulic engine embodying my invention;

Fig. 2 is a diagrammatic representation from the interior of a ship of the deck-edge elevator shown in Fig. 1 and its power system;

Fig. 3 is an enlarged representation of the power system for the elevator embodying my improved safety apparatus;

Fig. 4 is a top plan view of the mechanical parts of the apparatus applied to the hitches on the hoisting cables;

Fig. 5 is a top plan view of only the safety apparatus included in Fig. 4;

Fig. 6 is a view in side elevation of the mechanical parts of my safety apparatus applied to the cable hitches of the elevator, some parts of the walls of the hitch boxes being broken away to disclose the safety parts more clearly;

Fig. 7 is a view in side elevation of only the mechanical parts of the safety apparatus shown in Fig. 6;

8 is a view in front'end elevation of the safety parts as applied to the cable hitches of the elevator; and

Fig. 9 is a view in end elevation of only the safety parts illustrated in Fig. 8.

My invention is illustrated in connection with a deck-edge elevator, such as is used on airplane carriers, ships for transferring airplanes from one deck to another. The elevator is operated by hoisting cables and is mounted on the outer side of the ship in alignment with a door opening 7 Claims. (Cl. 18'7-29) therein to the main deck and is movable up and down on the side of the ship to serve its main deck and its flight deck. The elevator is very large and the weights carried by the hoisting cables are correspondingly heavy. However, it is to be understood that the invention may be employed with elevators used for other purposes.

Referring more particularly to Figs. 1 and 2, I have illustrated a deck-edge elevator comprising an elevator platform disposed between a pair of guide rails l I and I2 mounted on the outer side of a ship hull l3 by a plurality of brackets E4. The platform is supported by and is raised and lowered between the main deck l5 and the flight deck "5 by a plurality of hoisting cables I! and I8 operated by a hydraulic hoisting englue [9. A plurality of rollers 2| are mounted on the ends of the platform in position to engage a pair of vertical slots 22 in the sides of the guide rails facing each other, for guiding the platform as it is raised or lowered.

The platform l9 comprises a base-section 23 and a hinged or outboard section 24 which normally lie in the same plane and provide a large level area upon which airplanes may be moved from either deck to the other. The base 23 is constructed with a suitable floor 25 mounted on a frame of high tensile steel tubing 26 welded together in bridgelike construction to form a relatively light but strong body or frame. The outboard section is constructed with a floor 21 and a frame 28 in a similar manner and is mounted upon and connected to the base 23 by a suitable hinge joint 29 so that it may be raised from its horizontal position into a vertical position on the base to permit the ship to pass through a lock or other narrow opening.

The hoisting engine [9 is a hydraulic engine comprising a single cylinder 34 mounted in a horizontal position on a frame or engine bed 35 and a power plunger 35 disposed in the cylinder. The outer end ofthe plunger is provided with a power head 31 in which a pair of power sheaves 38 are rotatably mounted. The plunger in the cylinder moves back and forth horizontally and thus moves the power sheaves back and forth with it. 1

The plunger is designed for operation by a suitable hydraulic medium such as oil placed under pressure by any suitable equipment such as a pressure tank 40, an exhaust tank 4| and a pressure pump 42. A pump motor 43 is provided for driving the pressure pump 42. The pressure system is connected to the cylinder through a pair of pipes 44 and 45 controlled by a suitable valve 45 mounted on the engine cylinder and connected for operation by a valve motor 41. Ihe valve 46 may be of any suitable type which shuts off and stops the flow of oil into the cylinder when the motor 4'! is stopped. The stopping of the flow of oil into the cylinder stops the movement of the plunger and the movement of the elevator, as the plunger remains stationary as long as no oil enters or leaves the cylinder. The pump motor 43 and the valve motor may be connected to any suitable source of electrical energy by supply conductors such as L+ and L- controlled by a pair of line switches 5I.

The motor 43 is provided with a controller 43C connected to and responsive to a suitable pressure device 5| in the upper part of the pressure tank to provide a means for controlling the operation of the motor in accordance with the pressure in the tank so that the motor will start the pump when the pressure falls below a predetermined value and will stop the pump when the pressure reaches a predetermined value.

A controller TC is disposed in the circuit of the valve motor 41 to be connected to any suitable control operating means (not shown) whereby the valve motor may be controlled to operate the valve 46 to raise or lower the elevator.

A pair of down stopping blocks 48 are mounted on the cylinder block in position to limit the rearward movement of the plunger and a pair of up stopping blocks 49 are mounted on a projection 50 seated on the engine bed in position to limit the forward movement of the plunger when the platform is being raised to the flight deck.

The hoisting cables H at the lefthand of the platform are secured to the base 23 by suitable hitches 52 mounted thereon and pass upwardly and over an idler sheave 53 fastened to the ship structure underneath the overhanging portion of the flight deck, thence rearwardly over a second idler sheave 54 mounted on the ship frame inside the hull, thence downwardly and under a deflector sheave 55 mounted on the engine bed 35, thence around a stationary sheave 56 mounted on the engine bed, thence around one of the power sheaves 38 and thence to a plurality of hitches 51 mounted on the lower part of the rear end of the engine.

The hoisting cables II! at the righthand end of the platform are secured to the base 20 by bracket 58 mounted thereon and pass upwardly and over an idler sheave 59 fastened to the ship structure underneath the overhanging portion of the flight deck, thence rearwardly over a second idler sheave 60 mounted on the ship frame inside the hull and thence downwardly and under a defiector sheave 6| mounted on the engine bed and thence under and over one of the power sheaves 38 mounted in the plunger head and thence to dead end hitches 62 mounted on the upper part of the rear end of the engine.

As illustrated in Fig. 4, the upper cable hitch 62a comprises a socket 84 mounted on the end of the cable, a rod 65 secured in the outer end of the socket by a pivot pin 66 with the outer end of the cable rod extending through the walls 61 and 68 of a hitch box 69 mounted on the top part of the rear end of the engine, and a pair of nuts I0 disposed on the rod beyond the wall 61 by means of which the eilective length of the cable may be adjusted. Each of the cable hitches 62 is constructed and mounted in the same manner. The cable hitches 51 are also constructed in the same manner with their rods extending through the walls II and I2 of a hitch box I3 mounted on the bottom part of the rear end of the engine. The nuts Iii provide a means by which, in connection with any well known cable tension tester, the effective length of the cables may be so ad- J'usted that the tension of each one will equal that of each other.

In order to avoid any serious accident resulting from the failure of any one or more of the cables by reason of breaking or loosening I have provided a safety device comprising a means for stopping the engine and the platform such as a safety switch I4 for operating a relay I5 to open the circuits for the valve motor and the pump motor when a cable breaks or loosens; a spanning lever It for operating the switch, a plurality of trip rods I1, I8, "I9 and for operating the spanning levers and aplurality of energy storing devices such as coiled springs SI, 82, 83, M, 85, 85, 81 and SB and actuators or spring washers 90, 9|, 92, 93, 94, 95, 96 and 91 mounted on the hitch rods for operating the trip rods. The washer 9D is provided with a collar or body 98 so that it constitutes a half spool like device and it is mounted concentrically on the rod between the nuts ID and the wall 61. Thespring 8| is concentrically mounted on the body 98 of the washer and is held between the washer and the wall 61 so that the nuts Ill may be tightened against the tension of the cable 62a until they hold the washer body tightly against the body 61 and thus compress the spring BI into the space between the washer and the wall. Inasmuch as the washer and its body and the nuts are solidly against the wall, they provide a deadend hitch for the cable. The uncompressed length and strength of the spring and the length of the washer body are so selected that the normal tension of the cable will not be overcome by the spring and it will thus store energy to move the hitch rod outwardly upon failure of the cable but it will not move the rod outwardly as long as the cable maintains its normal tension. The other springs and washers are mounted on the other cable rods in the same manner.

The trip rods TI and I8 are connected at their bases by a yoke I00 so that they form an integral structure, and the bases of the trip rods I9 and 80 are connected by a yoke I DI which in turn is connected to a shaft I02 so that they constitute an integral structure. The trip rods 11 and I8 are provided with notched or shouldered portions I03,

I04 and I05 and are slidably disposed in the walls 61 and 68 of the hitch box 69 in position approximately parallel to the hitch rods 65 with the washer 90 in the notch I03 and the washer GI in the notch I34 and the washers 92 and 93 in the notch I55. The trip rods I9 and 80 are provided with notched or shouldered portions I06, I 01 and H38 and are slidably disposed in the walls TI and T2 of the hitch box I3 in position approximately parallel with the rods 51 and with the washer 94 in the notch I 05, the washer 95 in the notch I 01 and the washers 95 and 91 in the notch The trip rods are held with their shoulders formed by the notches against the outer faces of the washers and the length of each notch is sufficient to permit the trip rods to move outwardly under the action of any one or more of the washers sufficiently to operate the safety apparatus without touching the rear faces of any of the other washers. With this arrangement of the trip rods and washers, the breaking or dangerous loosening of any one of the cables will permit its rod to move outwardly under the energy stored in the compression spring thereon and thus cause its spring washer to engage the shoulder portion of the trip rod With which it is associated and move it outwardly, without affecting any other cable hitch.

The spanning lever is mounted with its forked upper end I09 resting in the bottom of the notch I05 of the trip rod I8 and its lower end H resting on a pin III in the outer end of the shaft I02 and it is maintained in this position by a biasing compression spring H2 mounted by a stud bolt H3 disposed in the rear end of the engine cylinder. The compression spring H2 lies between the nut on the stud bolt and the outer face of the spanning lever so that it presses or biases the lever toward the rear end of the engine cylinder and causes its ends I09 and H0 to press the trip rods to the left to maintain them in their normal position against the spring washers 90, 9I, etc.

Inasmuch as the yoke I00 connects the trip rods H and I8, the outward movement of either rod will move both of them outwardly so that the rod 18 presses against the upper end I09 of the spanning lever and moves it outwardly. Also, inasmuch as the yoke I0! connects the rods I9 and 80 and the shaft I02, the outward movement of either trip rod I9 or 80 will move both of them and the shaft I02 outwardly against the lower end IIO of the spanning lever and thus move it outwardly.

The switch I4 is mounted on a bar I I6 welded or otherwise secured to the engine bed 35 and is provided with a switch arm H? on the outer end of which is disposed a roller H8 in position to rest against the outer central portion of the spanning lever l so that any outward movement of the spanning lever will move the switch arm I II to open switch position.

The relay I5 may be mounted in any suitable position with the one lead to its coil a connected to the supply conductor L- and its other lead extending through the switch I4 to the supply conductor L+ so that the relay will remain energized as long as the switch I4 is in its closed position but will be deenergized when the spanning lever I0 moves the switch arm to open switch position. The relay I5 is provided with contacts 15b to close the circuit to the valve motor 41 and with contacts I50 to close the circuit to the pump motor 43 to cause these circuits to remain in operative condition as long as the relay remains energized but to open these circuits for the purpose of stopping the valve motor and the pump when the relay is deenergized.

In an assumed operation of the elevator, with the platform at the lower deck, the valve 46 on the engine 19 is operated to admit oil under pressure to the cylinder. As the oil flows into the cylinder, it forces the plunger forward and thereby moves the power sheaves 38 to the left. As the power sheaves move toward the left, they exert a pull on the hoisting cables I1 and I8 and thus cause them to raise the platform I0 until it is even with the flight deck.

As the platform approaches the flight deck, the valve 46 is operated to decrease the amount of oil being admitted to the engine cylinder 36 to zero, and the pressure of the oil in the cylinder now maintains the plunger against the cables with suflicient force to hold the platform in its upper position.

It is assumed now that the platform is to be lowered to the main deck and that the valve is operated to permit the oil in the cylinder 36 to escape to effect this result. The escape of the oil from the cylinder permits the plunger to move rearwardly under the pressure exerted by the weight of the platform; As the plunger nears the end of its rearward stroke, the valve 46 is operated to its closed position and the plunger reaches the down stopping blocks 48 and is stopped to hold the platform at the main deck.- The down stopping blocks and the lengths of the cables are so adjusted that the platform is in position to serve the main deck when the plunger is stopped :by its down stopping blocks.

It will be assumed now that while the elevator is being raised from the lower deck to the upper deck the cable 02a breaks or becomes loosened to such an extent that it becomes dangerous and thereby permits th energy stored in the spring 8| to move the washer. and the hitch rod 05 outwardly, thus moving the washer 90 against the notched portion I03 of the trip rod 11. The pressure of the washer 90 against the trip rod 11 moves it outwardly and with it the yoke I00 and the trip rod I8. The outward movement of the trip rod I8 forces the upper end I09 of the spanning lever outwardly by reason of the position of its lower end H0 on the shaft I02 and thereby pushes the switch arm I I1 outwardly until it opens the switch I4 thereby deenergizing the relay I5. The deenergized relay 15 opens its contacts 15b and its contacts thus deenergizing the valve motor 41 and pump motor #3 to immediately stop all operations of the hoisting system.

If any two of the cables break simultaneously, for instance, those attached to the hitch rods I20 and 12d (Fig. 4), the washers 96 and 91 disposed in the notch 508 of trip rod I9 and against the righthand shoulder formed by that notch will force the rod outwardly and the rod will force the lower end of the spanning lever outwardly. The outward movement of the lower end of the spanning lever will pivot the lever on its upper end in the notch I05 of the trip rod 18 and thus open the switch I4 by moving the switch arm I I1 outwardly. The opening of the switch I4 will deenergize the switch I5 and thereby open the circuits for the valve motor and pump motor to shut down the hoisting system of the elevator.

B reason of the foregoing description, it will be seen that I have provided a reliable and safe system which will stop any further operation of the elevator as soon as any one or any number of the hoisting cables break or loosen to a dangerous degree. It will also be evident that the apparatus is sturdy and so simple in nature that it cannot easily get out of order and that it will operate effectively regardless of only one cable breaking or half a dozen cables breaking simultaneously. It will also be apparent that the apparatus may be inspected easily and that it will be inexpensive to maintain in operation.

Although I have illustrated and described only one specific embodiment of my invention, it is to be understood that changes therein and modifications thereof may be made without departing from the spirit and scope of the invention.

I claim as 'my invention:

1. In an elevator, a plotform for serving a lower floor and an upper floor, a plurality of hoisting cable for raising and lowering the platform, an engine for operating the hoisting cables, a hitch box, a hitch rod connected to each cable and slidably mounted in the hitch box, an energy storing device disposed on each hitch rod to store energy when its cable is under tension for moving that hitch rod outwardly upon failure of its cable, a plurality of trip rods slidably mounted approximately parallel to the hitch rods in the hitch box, a yoke connecting the trip rods into an integral structure, an actuator mounted on each hitch rod and responsive to outward movement of that hitch rod for moving the trip rod structure outwardly and means responsive to outward movement of the trip rod structure for stopping the engine and the platform.

2. In an elevator, a platform for serving a lower floor and an upper floor, a plurality of hoisting cables for raising and lowering the platform, an engine or operating the hoisting cables, a hitch box, a hitch rod connected to each. cable and slidably mounted in the hitch box, an energy storing device disposed on each hitch rod to store energy when its cable is under tension for moving that hitch rod outwardly upon failure of its cable, a trip rod slidably disposed in the hitch box and provided with shoulder portions, an actuator mounted on each hitch rod and disposed against a shoulder portion of the trip rod whereby a predetermined outward movement of any one or more of the hitch rods will cause outward movement of the trip rod, and means responsive to outward movement of the trip rod for stopping the engine.

3. In an elevator, a platform for serving a lower floor and an upper floor, a plurality of hoisting cables for raising and lowering the platform, an engine for operating the hoisting cable's, a hitch rod connected to each cable and slidably mounted on the engine, an energy storing device disposed on each hitch rod for storing energy when its cable is under tension to move that hitch rod ou wardly upon failure of its cable, a trip rod slidably disposed on the engine in approximately parallel relation to the hitch rods, a connector mounted on each hitch rod for engaging the trip rod and moving it outwardly when that hitch rod is moved outwardly by failure of its cable, and means responsive to an outward movement of the trip rod for stopping the engine.

4. In an elevator, a latform for serving a lower floor and an upper floor, a plurality of hoisting cables for raising and lowering the platform. an engine for operating the hoisting cables, a hitch rod connected to each cable and slidably mounted on the engine, a compression spring mounted on each hitch rod between the end of the rod and the engine to store energy when the cable is under tension for moving that hitch rod outwardly upon failure of its cable, a washer mounted on each hitch rod between the spring and the end of the rod, a trip rod slidably disposed on the engine in approximately parallel relation to the hitch rods and provided with notches for receiving the edges of the washers, a spanning lever pivotally mounted on the engine in position to be moved outwardly by a predetermined outward movement of the trip rod, and means responsive to a predetermined outward movement of the spanning lever for stopping operation of the elevator platform.

5. In an elevator ,a platform for serving a lower floor and an upper floor, a plurality of hoisting cables for raising and lowering the platform, an engine for operating the hoisting cables, control means for the engine, a hitch. box associated with the engine, a hitch rod connected to each cable and slid-ably mounted in the hitch box, a nut on the outer end of each hitch rod for adjusting the effective length of its cable, a compression spring disposed on each hitch rod between its nut and the hitch box for storing energy when the cable is under tension to move that hitch rod outwardly upon failure of its cable, a washer mounted on each hitch rod between the spring and the nut thereon, the periphery of said washer extending beyond the sides of the spring, a collar for limiting the compression of the spring, a plurality of trip rods connected into an integral structure and slidably disposed in the hitch box in approximately parallel relation to the hitch rods and provided with notches for receiving the edges of the spring washers, whereby a predetermined outward movement of a washer will move the trip rod structure outwardly, a switch connected in the control circuit for the motive means, a spanning lever pivotally mounted on the engine with one portion disposed in engagement with one of the trip rods and another portion disposed in engagement with the switch whereby outward movement of the trip rod structure will cause the lever to move the switch to open position and thereby stop operation of the engine, and resilient means for biasing the spanning lever against the trip rod structure.

6. In an elevator, a platform for serving an upper floor and a lower fioor, a first set of hoisting cables attached to one end of the platform, a second set of hoisting cables attached to the other end of the platform, a hydraulic engine for operating the hoisting cables, a first hitch box for the first set of cables, 21 second hitch box for the second set of cables, a first set of hitch rods, one for each of the first set of cables, slidably mounted in the first hitch box for connecting the first set of cables to that hitch box, a second set of hitch rods, one for each of the second set of cables, slidably mounted in the second hitch box for connecting the second set of cables to that bitch box, an energy storing device on each hitch rod and responsive to the tension in its cable for moving it outwardly upon failure of that cable, a plurality of trip rods slidably disposed in each hitch box approximately parallel to the hitch rods therein, a yoke connecting the trip rods in the first hitch box into an integral structure, a second yoke connecting the trip rods in the second hitch box into an integral structure, a connector associated with each hitch rod in the first hitch box and the trip rods therein for moving the trip rods in that box outwardly upon failure of any cable attached to a hitch rod in that box, a connector associated with each hitch rod in the second hitch box and the trip rods therein for moving them out wardly upon failure of any cable attached to a hitch rod in that hitch box, a spanning lever pivotally mounted on the engine with its one end connected with one of the trip rods in the first hitch box and its other end connected with one of the trip rods in the second hitch box, means for biasing the spanning lever against the trip rods, and a switch responsive to operation of the lever by the trip rods in either hitch box for stopping the operation of the engine upon failure of any one of the hoisting cables.

'7. In an elevator system, a platform for serving an upper floor and a lower floor, a first set of cables for one end of the platform. a second set of cables for the other end of the platform, an engine for operating the cables, a first hitch box for the first set of cables, a second hitch box for the second set of cables, a plurality of hitch rods, one for each of the first set of cables, slidably mounted in the first hitch box, a second set of hitch rods, one for each of the second set of 9 cables, slidably mounted in the second hitch box, a compression spring disposed on each hitch rod and responsive to the tension of the cable attached thereto for moving that hitch rod outwardly upon failure of that cable, an actuator mounted on each hitch rod, a plurality of trip rods slidably disposed in each hitch box and provided with notches intermediate their ends disposed to receive the ends of the actuators on the hitch rods associated therewith so that the outward movement of any hitch rod will move the trip rod associated with it outwardly, a yoke connecting the trip rods in the first hitch box to form an integral structure, a second yoke connecting the trip rods in the second hitch box into an integral structure, a shaft mounted on the outer end of the second yoke and disposed approximately parallel to the trip rods attached to the yoke, a spanning lever pivotally mounted with its one end in pivotal contact with one of the trip rods in the first hitch box and its other end in contact with the shaft attached to the trip rods in the second hitch box, resilient means for biasing the spanning lever against the trip rods, and means responsive to operation of the lever by either one of the trip rod structures for stopping the operation of the engine upon failure of any one of the hoisting cables.

JAMES DUNLOP. 

